▶️ Answer/Explanation
Gravitropism is the growth of a plant root or shoot in response to the direction of gravity.
Growth occurs because the plant produces new cells and elongates towards or away from gravity.
Sensitivity is shown because the plant detects the gravitational stimulus and responds to it.
✅ Answer: (B)
Growth occurs because the plant produces new cells and elongates towards or away from gravity.
Sensitivity is shown because the plant detects the gravitational stimulus and responds to it.
✅ Answer: (B)
▶️ Answer/Explanation
Oxygen concentration is higher in the alveolar air than in the blood capillaries.
Molecules move down their concentration gradient without using energy.
This passive movement of oxygen into the blood is diffusion.
✅ Answer: (A)
Molecules move down their concentration gradient without using energy.
This passive movement of oxygen into the blood is diffusion.
✅ Answer: (A)
▶️ Answer/Explanation
Oils are lipids made of fatty acids joined to glycerol.
The enzyme lipase catalyses the hydrolysis of lipids during digestion.
This breaks the lipid down into its building blocks, fatty acids and glycerol.
✅ Answer: (C)
The enzyme lipase catalyses the hydrolysis of lipids during digestion.
This breaks the lipid down into its building blocks, fatty acids and glycerol.
✅ Answer: (C)
▶️ Answer/Explanation
The stomach is the wide, J-shaped sac just after the oesophagus.
The liver is the large organ above and to the side of the stomach, while the pancreas lies behind the stomach near the small intestine.
Matching each labelled structure to its position in the alimentary canal gives the correct set for liver, pancreas and stomach.
✅ Answer: (D)
The liver is the large organ above and to the side of the stomach, while the pancreas lies behind the stomach near the small intestine.
Matching each labelled structure to its position in the alimentary canal gives the correct set for liver, pancreas and stomach.
✅ Answer: (D)
▶️ Answer/Explanation
Water vapour is lost mainly through the stomata on the lower epidermis by diffusion to the air outside.
Carbon dioxide for photosynthesis also enters through the stomata and diffuses to the palisade and spongy mesophyll cells.
The labelled cells closest to the stomatal pore and air spaces are responsible for the most water loss and carbon dioxide uptake.
✅ Answer: (A)
Carbon dioxide for photosynthesis also enters through the stomata and diffuses to the palisade and spongy mesophyll cells.
The labelled cells closest to the stomatal pore and air spaces are responsible for the most water loss and carbon dioxide uptake.
✅ Answer: (A)
▶️ Answer/Explanation
Iodine solution turns blue-black in the presence of starch and stays brown if starch is absent.
Saliva contains amylase, an enzyme that breaks starch down into sugars.
Since the iodine stays brown, the starch has been chemically broken down, which is digestion.
✅ Answer: (C)
Saliva contains amylase, an enzyme that breaks starch down into sugars.
Since the iodine stays brown, the starch has been chemically broken down, which is digestion.
✅ Answer: (C)
▶️ Answer/Explanation
Red blood cells appear as small, round, biconcave discs without a nucleus in a blood smear.
They are distinguished from the larger, nucleus-containing white blood cells also visible in the field of view.
Counting only the red, disc-shaped cells in the diagram gives the total number present.
✅ Answer: (D)
They are distinguished from the larger, nucleus-containing white blood cells also visible in the field of view.
Counting only the red, disc-shaped cells in the diagram gives the total number present.
✅ Answer: (D)
▶️ Answer/Explanation
During respiration, the body uses up oxygen and produces carbon dioxide.
Expired air therefore has less oxygen and more carbon dioxide than inspired air.
Expired air is also saturated with water vapour from the moist lung surfaces, so water vapour increases.
✅ Answer: (B)
Expired air therefore has less oxygen and more carbon dioxide than inspired air.
Expired air is also saturated with water vapour from the moist lung surfaces, so water vapour increases.
✅ Answer: (B)
▶️ Answer/Explanation
Hormones are chemical messengers released by glands and carried in the blood to a target organ.
Each correct row must match a named hormone with both its true gland of secretion and its true effect on the body.
Checking each row against known hormone facts, such as insulin from the pancreas lowering blood glucose, identifies the only fully correct combination.
✅ Answer: (C)
Each correct row must match a named hormone with both its true gland of secretion and its true effect on the body.
Checking each row against known hormone facts, such as insulin from the pancreas lowering blood glucose, identifies the only fully correct combination.
✅ Answer: (C)
▶️ Answer/Explanation
Fertilisation usually occurs in the oviduct, and the resulting embryo then travels towards the uterus.
Normal implantation occurs in the lining (endometrium) of the uterus wall, which is thick and well supplied with blood vessels.
This lining provides nutrients and support needed for the embryo to develop into a healthy fetus.
✅ Answer: (D)
Normal implantation occurs in the lining (endometrium) of the uterus wall, which is thick and well supplied with blood vessels.
This lining provides nutrients and support needed for the embryo to develop into a healthy fetus.
✅ Answer: (D)
▶️ Answer/Explanation
A heterozygous genotype has two different alleles for a gene, for example Aa.
Because the alleles differ, the organism is not pure breeding, as it can pass on either allele.
This is different from a homozygous genotype, which has two identical alleles and is pure breeding.
✅ Answer: (A)
Because the alleles differ, the organism is not pure breeding, as it can pass on either allele.
This is different from a homozygous genotype, which has two identical alleles and is pure breeding.
✅ Answer: (A)
▶️ Answer/Explanation
A consumer is any organism that obtains its energy by eating other organisms.
Carnivores eat animals, not plants, so option A is incorrect.
Herbivores eat plants, not animals, so option C is incorrect, and producers make their own food rather than feeding on dead matter, so option D is incorrect.
✅ Answer: (B)
Carnivores eat animals, not plants, so option A is incorrect.
Herbivores eat plants, not animals, so option C is incorrect, and producers make their own food rather than feeding on dead matter, so option D is incorrect.
✅ Answer: (B)
▶️ Answer/Explanation
In darkness, plants cannot photosynthesise, so both plants and animals only respire.
Respiration takes in oxygen and releases carbon dioxide, so the carbon cycle gas involved is carbon dioxide, not oxygen.
Identifying the arrows that represent carbon dioxide being released by both groups of organisms gives the gases that are part of the carbon cycle.
✅ Answer: (B)
Respiration takes in oxygen and releases carbon dioxide, so the carbon cycle gas involved is carbon dioxide, not oxygen.
Identifying the arrows that represent carbon dioxide being released by both groups of organisms gives the gases that are part of the carbon cycle.
✅ Answer: (B)
▶️ Answer/Explanation
An element is made of only one type of atom, so the atom is its smallest unit.
Atoms of the same element can have different numbers of neutrons, called isotopes, so B is wrong.
Protons and neutrons are not always equal in number, and the Periodic Table is ordered by proton number, not mass number, so A and C are wrong.
✅ Answer: (D)
Atoms of the same element can have different numbers of neutrons, called isotopes, so B is wrong.
Protons and neutrons are not always equal in number, and the Periodic Table is ordered by proton number, not mass number, so A and C are wrong.
✅ Answer: (D)
▶️ Answer/Explanation
Helium is a noble gas that exists as single, separate atoms, not molecules.
Chlorine exists as a covalent diatomic molecule, \(Cl_2\), and ethanol is a covalent molecular compound.
Sodium chloride is an ionic compound, not a covalent molecule, so it is excluded.
✅ Answer: (C)
Chlorine exists as a covalent diatomic molecule, \(Cl_2\), and ethanol is a covalent molecular compound.
Sodium chloride is an ionic compound, not a covalent molecule, so it is excluded.
✅ Answer: (C)
▶️ Answer/Explanation
Graphite is made of carbon atoms arranged in flat hexagonal layers.
Each carbon atom is covalently bonded to three others within its layer, leaving weak forces between separate layers.
The diagram showing this layered hexagonal sheet structure, rather than a 3D tetrahedral lattice, represents graphite.
✅ Answer: (A)
Each carbon atom is covalently bonded to three others within its layer, leaving weak forces between separate layers.
The diagram showing this layered hexagonal sheet structure, rather than a 3D tetrahedral lattice, represents graphite.
✅ Answer: (A)
▶️ Answer/Explanation
\(NO_2\) has a nitrogen to oxygen ratio of \(1:2\).
\(N_2O_4\) simplifies to the same ratio, \(1:2\), when divided by 2.
\(N_2O\) has a ratio of \(2:1\) and \(NO\) has a ratio of \(1:1\), so neither matches.
✅ Answer: (D)
\(N_2O_4\) simplifies to the same ratio, \(1:2\), when divided by 2.
\(N_2O\) has a ratio of \(2:1\) and \(NO\) has a ratio of \(1:1\), so neither matches.
✅ Answer: (D)
▶️ Answer/Explanation
A gas syringe collects gas produced in a reaction and reads off its volume directly.
A balance measures mass, a pipette measures small liquid volumes, and a test-tube does not measure gas volume.
Only the gas syringe is designed to both collect and measure gas volume accurately.
✅ Answer: (B)
A balance measures mass, a pipette measures small liquid volumes, and a test-tube does not measure gas volume.
Only the gas syringe is designed to both collect and measure gas volume accurately.
✅ Answer: (B)
▶️ Answer/Explanation
Carbon starts with no oxygen and ends up combined with oxygen in \(CO_2\).
Gaining oxygen means carbon has been oxidised.
Meanwhile \(Fe_2O_3\) loses oxygen to form Fe, so it is reduced, not oxidised, ruling out C and D.
✅ Answer: (A)
Gaining oxygen means carbon has been oxidised.
Meanwhile \(Fe_2O_3\) loses oxygen to form Fe, so it is reduced, not oxidised, ruling out C and D.
✅ Answer: (A)
▶️ Answer/Explanation
Acidic waste starts with a pH below 7.
Limestone is a base (calcium carbonate) that neutralises the acid in the waste.
After treatment, the pH rises towards 7, so the correct row shows a low pH before and a higher, closer-to-neutral pH after.
✅ Answer: (B)
Limestone is a base (calcium carbonate) that neutralises the acid in the waste.
After treatment, the pH rises towards 7, so the correct row shows a low pH before and a higher, closer-to-neutral pH after.
✅ Answer: (B)
▶️ Answer/Explanation
A gas that turns limewater milky is carbon dioxide, showing X is a carbonate.
This rules out the chlorides, leaving lithium carbonate or potassium carbonate.
A red flame test is characteristic of lithium ions, not the lilac flame of potassium.
✅ Answer: (A)
This rules out the chlorides, leaving lithium carbonate or potassium carbonate.
A red flame test is characteristic of lithium ions, not the lilac flame of potassium.
✅ Answer: (A)
▶️ Answer/Explanation
Each mineral’s formula is checked element by element against the Periodic Table to classify each as a metal or non-metal.
Metals are mostly found on the left and centre of the Periodic Table, while non-metals are on the right.
Only one listed mineral has all three of its elements positioned among the non-metals.
✅ Answer: (C)
Metals are mostly found on the left and centre of the Periodic Table, while non-metals are on the right.
Only one listed mineral has all three of its elements positioned among the non-metals.
✅ Answer: (C)
▶️ Answer/Explanation
Transition elements are typical metals with strong metallic bonding.
This strong bonding gives them high melting points and high densities.
They are good thermal conductors, not insulators, and are opaque, not transparent, ruling out C and D.
✅ Answer: (A)
This strong bonding gives them high melting points and high densities.
They are good thermal conductors, not insulators, and are opaque, not transparent, ruling out C and D.
✅ Answer: (A)
▶️ Answer/Explanation
Mixing a metal with another element to form an alloy disrupts the regular arrangement of atoms.
Atoms of different sizes prevent layers of atoms from sliding over each other easily.
This makes the alloy harder than the pure metal.
✅ Answer: (B)
Atoms of different sizes prevent layers of atoms from sliding over each other easily.
This makes the alloy harder than the pure metal.
✅ Answer: (B)
▶️ Answer/Explanation
The three key fertiliser elements are nitrogen, phosphorus and potassium (NPK).
Potassium nitrate, \(KNO_3\), contains both potassium and nitrogen.
The other compounds (carbonate, chloride, sulfate) only supply potassium plus a non-fertiliser element.
✅ Answer: (C)
Potassium nitrate, \(KNO_3\), contains both potassium and nitrogen.
The other compounds (carbonate, chloride, sulfate) only supply potassium plus a non-fertiliser element.
✅ Answer: (C)
▶️ Answer/Explanation
Limestone is calcium carbonate, \(CaCO_3\).
Heating breaks it down into calcium oxide (lime) and carbon dioxide.
Breaking down one compound into simpler substances using heat is thermal decomposition.
✅ Answer: (D)
Heating breaks it down into calcium oxide (lime) and carbon dioxide.
Breaking down one compound into simpler substances using heat is thermal decomposition.
✅ Answer: (D)
▶️ Answer/Explanation
Addition polymerisation joins many small, identical molecules together into one long chain.
These small repeating units that join together are called monomers.
Here, ethene molecules are the monomers that link to form poly(ethene).
✅ Answer: (C)
These small repeating units that join together are called monomers.
Here, ethene molecules are the monomers that link to form poly(ethene).
✅ Answer: (C)
▶️ Answer/Explanation
On a speed–time graph, the distance travelled equals the area under the graph line.
For an object accelerating uniformly from rest to speed \(v\) over time \(t\), this area is a triangle.
The area of this triangle is \(\frac{1}{2}vt\).
✅ Answer: (C)
For an object accelerating uniformly from rest to speed \(v\) over time \(t\), this area is a triangle.
The area of this triangle is \(\frac{1}{2}vt\).
✅ Answer: (C)
▶️ Answer/Explanation
Density is calculated using \(\text{density} = \frac{\text{mass}}{\text{volume}}\).
The volume of the block is found by multiplying its three dimensions shown in the diagram, giving \(24\ \text{cm}^3\).
Dividing the mass by this volume, \(\frac{72}{24} = 3.0\), gives the density of the metal.
✅ Answer: (A)
The volume of the block is found by multiplying its three dimensions shown in the diagram, giving \(24\ \text{cm}^3\).
Dividing the mass by this volume, \(\frac{72}{24} = 3.0\), gives the density of the metal.
✅ Answer: (A)
▶️ Answer/Explanation
An object moving at constant speed in a straight line can have zero resultant force, so A is wrong.
Slowing down means the velocity is changing, which requires a resultant force to cause deceleration.
Forces in different directions, or of different sizes, can still combine to give a resultant, so C and D are wrong.
✅ Answer: (B)
Slowing down means the velocity is changing, which requires a resultant force to cause deceleration.
Forces in different directions, or of different sizes, can still combine to give a resultant, so C and D are wrong.
✅ Answer: (B)
▶️ Answer/Explanation
Wind is simply air that is moving.
Moving air has kinetic energy due to its motion.
The turbine blades are turned by this kinetic energy, which a generator then converts into electrical energy.
✅ Answer: (C)
Moving air has kinetic energy due to its motion.
The turbine blades are turned by this kinetic energy, which a generator then converts into electrical energy.
✅ Answer: (C)
▶️ Answer/Explanation
Heating a solid causes it to expand as its particles vibrate more and move further apart.
Heating the disc makes the hole in its centre expand, becoming large enough for the cylinder.
Cooling the disc would shrink the hole further, making it harder, not easier, to fit.
✅ Answer: (D)
Heating the disc makes the hole in its centre expand, becoming large enough for the cylinder.
Cooling the disc would shrink the hole further, making it harder, not easier, to fit.
✅ Answer: (D)
▶️ Answer/Explanation
Light travels more slowly in glass than in air because glass is the denser optical medium.
When light passes from glass into the less dense air, it speeds up and bends away from the normal.
The arrow that bends away from the normal line at the glass-air boundary shows the correct refracted path.
✅ Answer: (D)
When light passes from glass into the less dense air, it speeds up and bends away from the normal.
The arrow that bends away from the normal line at the glass-air boundary shows the correct refracted path.
✅ Answer: (D)
▶️ Answer/Explanation
A wave’s amplitude relates to the loudness of the sound, and its frequency (number of waves per unit time) relates to the pitch.
Comparing waves P and Q drawn to the same scale shows differences in their amplitude and/or wavelength.
The statement that correctly links these differences to changes in loudness and pitch is the correct one.
✅ Answer: (D)
Comparing waves P and Q drawn to the same scale shows differences in their amplitude and/or wavelength.
The statement that correctly links these differences to changes in loudness and pitch is the correct one.
✅ Answer: (D)
▶️ Answer/Explanation
Rubbing two insulating materials together transfers electrons from one material’s surface to the other.
The material that loses electrons becomes positively charged, since it now has more protons than electrons.
The material that gains those electrons becomes negatively charged, since it now has more electrons than protons.
✅ Answer: (C)
The material that loses electrons becomes positively charged, since it now has more protons than electrons.
The material that gains those electrons becomes negatively charged, since it now has more electrons than protons.
✅ Answer: (C)
▶️ Answer/Explanation
Current is measured in amperes and resistance is measured in ohms, not volts.
Electromotive force (e.m.f.) describes the energy supplied per unit charge by a source, measured in volts.
Potential difference (p.d.) describes energy transferred per unit charge across a component, also measured in volts.
✅ Answer: (B)
Electromotive force (e.m.f.) describes the energy supplied per unit charge by a source, measured in volts.
Potential difference (p.d.) describes energy transferred per unit charge across a component, also measured in volts.
✅ Answer: (B)
▶️ Answer/Explanation
In a series circuit, there is only one path for charge to flow, so current has nowhere else to go.
This means the current must be the same at every point in the circuit, including through both resistors and the cell.
The resistor values do not split the current in series, ruling out options A, C and D.
✅ Answer: (B)
This means the current must be the same at every point in the circuit, including through both resistors and the cell.
The resistor values do not split the current in series, ruling out options A, C and D.
✅ Answer: (B)
▶️ Answer/Explanation
Increasing the current, using a stronger magnet, or using more turns all increase the turning effect.
Reversing the current direction only reverses the direction of rotation of the coil.
The magnitude of the turning effect itself stays the same when only the current direction is reversed.
✅ Answer: (A)
Reversing the current direction only reverses the direction of rotation of the coil.
The magnitude of the turning effect itself stays the same when only the current direction is reversed.
✅ Answer: (A)
▶️ Answer/Explanation
The proton number (bottom number) is given as 38.
The mass number (top number) equals protons plus neutrons, so \(38 + 52 = 90\).
Nuclide notation places the mass number above the proton number, giving \(^{90}_{38}\textrm{Sr}\).
✅ Answer: (B)
The mass number (top number) equals protons plus neutrons, so \(38 + 52 = 90\).
Nuclide notation places the mass number above the proton number, giving \(^{90}_{38}\textrm{Sr}\).
✅ Answer: (B)
▶️ Answer/Explanation
Half-life is the time taken for the activity of a radioactive substance to fall to half its original value.
Reading the graph, the activity drops from its starting value to half that value over a certain time interval.
This time interval read off the graph is the half-life of the substance.
✅ Answer: (A)
Reading the graph, the activity drops from its starting value to half that value over a certain time interval.
This time interval read off the graph is the half-life of the substance.
✅ Answer: (A)